Officials try to find what killed invasive carp

SIOUX CITY, Iowa (AP) - Wildlife officials are trying to figure out what killed hundreds of Asian carp in the Missouri River this spring.  The answer to the mystery could help protect other fish, and it might provide clues to dealing with the invasive carp.  Fisheries biologist Jeff Schuckman says no one has come up with a good explanation for the fish kill.  The rotting carcasses of hundreds of silver carp were found in the river's slow backwaters near Vermillion, S.D., and Ponca, Neb. Another incident was reported in Nebraska North Platte River near where it joins the Missouri River.  Both fish kills were reported in May.